1. Field of the Invention
The invention relates in general to an injection-locked frequency divider, and more particularly to an injection-locked frequency divider with a wide injection-locked frequency range.
2. Description of the Related Art
The frequency divider is one of the indispensable and essential components in the present wireless communication system, which is used for receiving an original signal and reducing the frequency of the signal by dividing it by one or a number of different values.
The injection-locked frequency divider is a commonly-used high frequency divider, which integrates a signal injection unit and a voltage controlled oscillator (VCO), such as a LC tank oscillator to divide the frequency of an injection signal.
However, the conventional injection-locked frequency divider has a very narrow injection-locked frequency range. If the injection signal has a frequency falling outside the injection-locked frequency range of the injection-locked frequency divider due to process or temperature variation, the injection-locked frequency divider will have malfunction. Therefore, how to design an injection-locked frequency divider with a wide injection-locked frequency range is a target for the relevant industrials to be engaged in.